Reflective microstructured films with microstructures having curved surfaces, for use in solar modules

Abstract

Reflective microstructured films include a base layer, and an ordered arrangement of a plurality of microstructures projecting from the base layer. The microstructures have a cross section with at least two sides, at least one of these sides is a curved surface. Each curved surface is defined by an angle of curvature. Additionally, the microstructures include a reflective layer. These reflective microstructured films can be used in solar modules.

What is claimed is: 
     
         1 . A reflective film comprising:
 a base layer; and   an ordered arrangement of a plurality of microstructures projecting from the base layer,   the microstructures having a cross section comprising at least two sides, wherein at   least one of the sides comprises a curved surface defined by an angle of curvature, and   wherein the microstructures comprise a reflective layer.   
     
     
         2 . The reflective film of  claim 1 , wherein the microstructures protrude 5 micrometers to 500 micrometers from the base layer. 
     
     
         3 . The reflective film of  claim 1 , wherein all of the at least two sides comprise curved surfaces, and wherein the angle of curvature of the curved surfaces is the same. 
     
     
         4 . The reflective film of  claim 1 , wherein the angle of curvature is greater than 0° and less than or equal to 9°. 
     
     
         5 . The reflective film of  claim 1 , wherein the base layer comprises a polymeric layer. 
     
     
         6 . The reflective film of  claim 1 , wherein the microstructures comprise a polymeric material. 
     
     
         7 . The reflective film of  claim 6 , wherein the microstructures comprise the same polymeric material as the base layer. 
     
     
         8 . The reflective film of  claim 6 , wherein the microstructures comprise a different polymeric from the base layer. 
     
     
         9 . The reflective film of  claim 1 , wherein the reflective layer comprises a metallic coating. 
     
     
         10 . The reflective film of  claim 9 , wherein the metallic coating comprises aluminum, silver, or a combination thereof. 
     
     
         11 . The reflective film of  claim 1 , wherein the peaks of the microstructures are rounded. 
     
     
         12 . A solar module comprising:
 a plurality of solar cells; and   a reflective film, the reflective film comprising:
 a base layer; and 
 an ordered arrangement of a plurality of microstructures projecting from the base layer, the microstructures having a cross section comprising at least two sides wherein at least one of the sides comprises a curved surface defined by an 
 angle of curvature, and wherein the microstructures comprise a reflective layer. 
   
     
     
         13 . The solar module of  claim 12 , wherein the microstructures protrude 5 micrometers to 500 micrometers from the base layer. 
     
     
         14 . The solar module of  claim 12 , wherein the angle of curvature is greater than 0° and less than or equal to 9°. 
     
     
         15 . The solar module of  claim 12 , wherein the reflective layer comprises a metallic coating. 
     
     
         16 . The solar module of  claim 12 , wherein the reflective film is located adjacent to the solar cells and/or adjacent to tabbing ribbons connecting the solar cells. 
     
     
         17 . A method of preparing a solar module comprising:
 providing a reflective film, the reflective film comprising:
 a base layer; and 
 an ordered arrangement of a plurality of microstructures projecting from the base layer, the microstructures having a cross section comprising at least two 
 sides wherein at least one of the sides comprises a curved surface defined by an 
 angle of curvature, and wherein the microstructures comprise a reflective layer; 
   providing a plurality of solar cells arranged on a support substrate and connected by tabbing ribbons;   attaching the reflecting film to the solar cells and/or adjacent areas; and   attaching a transparent cover layer over the reflecting film.   
     
     
         18 . The method of  claim 17 , wherein the microstructures protrude 5 micrometers to 500 micrometers from the base layer. 
     
     
         19 . The method of  claim 17 , wherein the angle of curvature is greater than 0° and less than or equal to 9°. 
     
     
         20 . The method of  claim 17 , wherein the reflective layer comprises a metallic coating. 
     
     
         21 . The method of  claim 20 , wherein the metallic coating comprises aluminum, silver, or a combination thereof. 
     
     
         22 . The method of  claim 17 , wherein the peaks of the microstructures are rounded. 
     
     
         23 . The method of  claim 17 , wherein the reflecting film is attached adjacent to at least a portion of the tabbing ribbons.